Only in development
Tencil appears on your dev site while you work. Production builds leave it out, so the integration is safe to commit.
- What
- Visual feedback for coding agents
- What we did
- Strategy, design, development and AI
- Live at
- tencil.dev
Your agent builds fast, but can't see what you're looking at
Coding agents like Claude Code put a whole page together in minutes. Steering them is the slow part. You describe in words which button you mean, which component it lives in and what should change about it, then hope your agent finds the same element.
So we built Tencil. You point at the element in your running app and type what should change. Your agent gets the component, the source file and the markup along with it, so you never have to explain where things live.
Point at what should change
Press C, click an element and type your prompt. Start a new thread, or continue one your agent already worked in, so it knows what it did before. The reply shows up next to the page, and the change on the page itself as soon as your dev server reloads.
localhost:5173/pricing
From comment to change, without leaving the browser
You start Tencil once with npx tencil. From then on it sits as an overlay on your dev site, with Claude Code or T3 Code behind it, on Next.js, Vite or any other dev server.
Reviewing a whole page? Queue your comments and send them to your agent all at once. Every pin keeps its own thread, so you reply for another round or resolve it once it's right.
A pin on the element, with your prompt on it. Your agent gets the component, the source file and the markup along with it.
Runs on your own machine
There's no Tencil server and no account. Your dev site, a small daemon and your agent all live on your own laptop. And because Tencil is open source, you can read exactly what it does.
Locked to localhost
A small daemon on your laptop carries feedback to your agent. It answers only your own dev sites and turns others away.
Your agent, your login
Tencil hands your prompt to Claude Code or T3 Code on your laptop, signed in as you. It talks to its provider as it always does.
Tencil
Point at it. Fix it here.
One command in your project and Tencil is on your dev site. Works with Claude Code and T3 Code, on Next.js, Vite and any other dev server.